Oil-switch.



G. STERN.

OIL SWiTCH.

APPLICAHGN FILED JULY 21. 1913.

Patented Feb. 8, 1916.

Fig. l.

UNITED STATESPATENT OFFICE.

snone srnmv, or BERLIN, enitiraninnssionon. To GENERAL ELECTRIC COMPANY, A conroim'rron or NEW- Yonx.

, oIL-swmcn.

Speciflcatlon pf Letters Patent.

Patented-Feb. 8, 1916.

Application flied July 21, 1913. Seriallo. 780,102.

. of which the following isa specification.

My invention relates to devices for interrupting circuits in oil, and more particularly to oil switches and similar devices.

When. circuits carrying large amounts of energy are interrupted by means of con- I tacts which separate under oil, a decomposition of the oil is caused by the arc and the products of decomposition form an ex-' plosive mixture with the air above the oil level. This explosive mixture ma'y'easily be ignited by a glowing spark coming from the contacts and therefore may cause the destruction of the apparatus and endanger the surroundings. An attempt has been made to meet this difiiculty by tightly closing the oil receptacle of the oil switch so as to leave no air at all in the oil switch itself. Pressure equalization and the escape of the arc gases were provided for by means of a stand pipe filled with oil. As tests have shown, this arrangement has the disadvantage that the high pressures generated in the oil switch duringthe interruption of circuits carrying a large amount of energy cannot be controlled and are aptto cause the destruction of the oil vessel.

The object of the present invention is to minimize the danger due to the presence of an explosive mixture above the oil. To th1s end the present invention does not attempt to prevent entirely the formation of the explosive mixture previously referred to, but confines any explosion that may occur to a relatively small space. In the preferred construction this result is attained by a special formation of. the cover of the oil vessel. The invention will best be understood in connection with the accompanying drawing in which merely for purposes of illustration I have shown one of the many forms in which the invention may be embodied, and in which- Figure 1 is a bottom plan view of the cover of an oil vessel embodying my invention; and Fig. 2 is a longitudinal section of an oil switch with a top or cover such as shown in Fig. 1.

In the particular form of device shown in the drawings by way of example, the oil vessel a is provided with a cover I) which has a number of ribs 0 projecting downwardly into the oil d in the oil vessel. As a result of this construction the air cushion e above the oil is divided by the ribs 0 into a number of pockets or chambers which are closed at the upper end and are not in com munication, although all of them are open to the oil d which seals the lower ends. As clearly appears from 'the'drawing, the cover is provided with. a large number of perpen dicular ribs on the inner side, which are of such dimensions that they extend a little below the oil level when the oil switch is assembled. The number of ribs should be so selected that the air spaces or pockets are relatively small as compared to the entire amount of air between the oil level and the cover. It is immaterial whether the ribs.

cross each other, as shown in Fig. 1, or rlfii in only one direction, or whether the cast 4 metal body of the cover is so constructed in some other way that quite a large number of separate air chambers or pockets areformed above the oil. Care should be taken that in some suitable way the air can, if necessary, easily be removed from the air pockets.

What I claim as new and desire to secure by Letters Patent of the United States, is,-

1. In a circuit-interrupting device, the combination of a. vessel partially filled with oil, means for interrupting the circuit in said vessel beneath the oil, and means for dividing only the space above the oil into a plurality of non-communicating chambers open at the lower end only.

'2. A circuit-interrupting device comprising a vessel partially filled with oil, circuit terminals extending into said vessel to a point beneath the surface of the oil, and partitions extending through the space above tially filled with oil, relatively movable oooperating contacts mounted to separate 1n said vessel beneath the oil, and a cover for said vessel provided with a plurality of ribs extending downwardly into the oil to form a plurality of separate chambers open only to the oil. a

- 5. An oil switch comprising a vessel con: taining oil and having an air cushion above the oil, relatively movable cooperating contacts mounted to separate in said vessel be- 'neath the oil, and a cover for said vessel having a plurality of ribs extending downwardly from said cover to below the oil level to divide the air cushion into a plurality of separate air chambers and thereby restrict any ignition of explosive gases which may occur in said chambers.

In witness whereof, I have hereunto set my hand this 7th day of July, 1913.

GEORG STERN.

Witnesses RICHARD NEUMANN, WALTHER REINHARDH. 

